function[sys,x0,str,ts,simStateCompliance] = Tail_aerodynamics(t,x,u,flag)
%SFUNTMPL General MATLAB S-Function Template
% With MATLAB S-functions, you can define you own ordinary differential
% equations (ODEs), discrete system equations, and/or just about
% any type of algorithm to be used within a Simulink block diagram.
%
% The general form of an MATLAB S-function syntax is:
% [SYS,X0,STR,TS,SIMSTATECOMPLIANCE] = SFUNC(T,X,U,FLAG,P1,...,Pn)
%
% What is returned by SFUNC at a given point in time, T, depends on the
% value of the FLAG, the current state vector, X, and the current
% input vector, U.
%
% FLAG RESULT DESCRIPTION
% ----- ------ --------------------------------------------
% 0 [SIZES,X0,STR,TS] Initialization, return system sizes in SYS,
% initial state in X0, state ordering strings
% in STR, and sample times in TS.
% 1 DX Return continuous state derivatives in SYS.
% 2 DS Update discrete states SYS = X(n+1)
% 3 Y Return outputs in SYS.
% 4 TNEXT Return next time hit for variable step sample
% time in SYS.
% 5 Reserved for future (root finding).
% 9 [] Termination, perform any cleanup SYS=[].
%
%
% The state vectors, X and X0 consists of continuous states followed
% by discrete states.
%
% Optional parameters, P1,...,Pn can be provided to the S-function and
% used during any FLAG operation.
%
% When SFUNC is called with FLAG = 0, the following information
% should be returned:
%
% SYS(1) = Number of continuous states.
% SYS(2) = Number of discrete states.
% SYS(3) = Number of outputs.
% SYS(4) = Number of inputs.
% Any of the first four elements in SYS can be specified
% as -1 indicating that they are dynamically sized. The
% actual length for all other flags will be equal to the
% length of the input, U.
% SYS(5) = Reserved for root finding. Must be zero.
% SYS(6) = Direct feedthrough flag (1=yes, 0=no). The s-function
% has direct feedthrough if U is used during the FLAG=3
% call. Setting this to 0 is akin to making a promise that
% U will not be used during FLAG=3. If you break the promise
% then unpredictable results will occur.
% SYS(7) = Number of sample times. This is the number of rows in TS.
%
%
% X0 = Initial state conditions or [] if no states.
%
% STR = State ordering strings which is generally specified as [].
%
% TS = An m-by-2 matrix containing the sample time
% (period, offset) information. Where m = number of sample
% times. The ordering of the sample times must be:
%
% TS = [0 0, : Continuous sample time.
% 0 1, : Continuous, but fixed in minor step
% sample time.
% PERIOD OFFSET, : Discrete sample time where
% PERIOD > 0 & OFFSET < PERIOD.
% -2 0]; : Variable step discrete sample time
% where FLAG=4 is used to get time of
% next hit.
%
% There can be more than one sample time providing
% they are ordered such that they are monotonically
% increasing. Only the needed sample times should be
% specified in TS. When specifying more than one
% sample time, you must check for sample hits explicitly by
% seeing if
% abs(round((T-OFFSET)/PERIOD) - (T-OFFSET)/PERIOD)
% is within a specified tolerance, generally 1e-8. This
% tolerance is dependent upon your model's sampling times
% and simulation time.
%
% You can also specify that the sample time of the S-function
% is inherited from the driving block. For functions which
% change during minor steps, this is done by
% specifying SYS(7) = 1 and TS = [-1 0]. For functions which
% are held during minor steps, this is done by specifying
% SYS(7) = 1 and TS = [-1 1].
%
% SIMSTATECOMPLIANCE = Specifices how to handle this block when saving and
% restoring the complete simulation state of the
% model. The allowed values are: 'DefaultSimState',
% 'HasNoSimState' or 'DisallowSimState'. If this value
% is not speficified, then the block's compliance with
% simState feature is set to 'UknownSimState'.
%
% The following outlines the general structure of an S-function.
%
switch flag
 %%%%%%%%%%%%%%%%%%
 % Initialization %
 %%%%%%%%%%%%%%%%%%
 case 0
 [sys,x0,str,ts,simStateCompliance]=mdlInitializeSizes;
 %%%%%%%%%%%%%%%
 % Derivatives %
 %%%%%%%%%%%%%%%
 case 1
 sys=mdlDerivatives(t,x,u);
 %%%%%%%%%%
 % Update %
 %%%%%%%%%%
 case 2
 sys=mdlUpdate(t,x,u);
 %%%%%%%%%%%
 % Outputs %
 %%%%%%%%%%%
 case 3
 sys=mdlOutputs(t,x,u);
 %%%%%%%%%%%%%%%%%%%%%%%
 % GetTimeOfNextVarHit %
 %%%%%%%%%%%%%%%%%%%%%%%
 case 4
 sys=mdlGetTimeOfNextVarHit(t,x,u);
 %%%%%%%%%%%%%
 % Terminate %
 %%%%%%%%%%%%%
 case 9
 sys=mdlTerminate(t,x,u);
 %%%%%%%%%%%%%%%%%%%%
 % Unexpected flags %
 %%%%%%%%%%%%%%%%%%%%
 otherwise
 DAStudio.error('Simulink:blocks:unhandledFlag', num2str(flag));
end
 end 
%sfuntmpl
%
%=============================================================================
% mdlInitializeSizes
% Return the sizes, initial conditions, and sample times for the S-function.
%=============================================================================
%
function [sys,x0,str,ts,simStateCompliance]=mdlInitializeSizes
%
% call simsizes for a sizes structure, fill it in and convert it to a
% sizes array.
%
% Note that in this example, the values are hard coded. This is not a
% recommended practice as the characteristics of the block are typically
% defined by the S-function parameters.
%
sizes = simsizes;
sizes.NumContStates = 0;
sizes.NumDiscStates = 0;
sizes.NumOutputs = 6;
sizes.NumInputs = 6;
sizes.DirFeedthrough = 1;
sizes.NumSampleTimes = 1; % at least one sample time is needed
sys = simsizes(sizes);
%
% initialize the initial conditions
%
x0 = [];
%
% str is always an empty matrix
%
str = [];
%
% initialize the array of sample times
%
ts = [0 0];
% Specify the block simStateCompliance. The allowed values are:
% 'UnknownSimState', < The default setting; warn and assume DefaultSimState
% 'DefaultSimState', < Same sim state as a built-in block
% 'HasNoSimState', < No sim state
% 'DisallowSimState' < Error out when saving or restoring the model sim state
simStateCompliance = 'UnknownSimState';
end 
%mdlInitializeSizes
%
%=============================================================================
% mdlDerivatives
% Return the derivatives for the continuous states.
%=============================================================================
%
function sys=mdlDerivatives(t,x,u)
sys = [];
end 
%mdlDerivatives
%
%=============================================================================
% mdlUpdate
% Handle discrete state updates, sample time hits, and major time step
% requirements.
%=============================================================================
%
function sys=mdlUpdate(t,x,u)
sys = [];
end 
%mdlUpdate
%
%=============================================================================
% mdlOutputs
% Return the block outputs.
%=============================================================================
%
function sys=mdlOutputs(t,x,u)
global Density momentstore constm
u_1 = u(1);
v_1 = u(2);
w_1 = u(3);
t_pi = u(4);
t_ri = u(5);
alpha = u(6)+0.5*t_pi;
V = sqrt(u_1^2 + v_1^2 + w_1^2);
beta = asin(v_1/V);
X = 0.5*Density*V*V*0.4306*(-0.3181-0.2310*alpha^2);
Y = 0.5*Density*V*V*0.4306*0.1153*alpha*beta;
Z = 0.5*Density*V*V*0.4306*(0.3346+(-0.2729*alpha)+0.0884*beta);
F = [1 0 0;0 cos(t_ri) sin(t_ri);0 -sin(t_ri) cos(t_ri)]*[X;Y;Z];
L = 0;% beta*(-0.0054-0.0161*alpha)*0.5*Density*V*V*0.4306*0.656168;
%New Changes proposed
%M = (((-0.3486*3+3.3182*alpha+0.0975*beta-0.4184*beta^2-0.3053*alpha*V)*0.5*Density*V*V*0.4306*0.656168)*5);
%Changes being made
%M = (((-0.3486*3-3.3182*alpha+0.0975*beta0.4184*beta^2+0.3053*alpha*V)*0.5*Density*V*V*0.4306*0.656168)*5);
%New M with failure
%M = (((-0.3486*3-3.3182*0.5*alpha+0.0975*beta0.4184*beta^2+0.3053*0.5*alpha*V)*0.5*Density*V*V*0.4306*0.656168)*5);
% Original version
M =(((-0.3486*3+3.3182*alpha+0.0975*beta-0.4184*beta^2-0.3053*alpha*V)*0.5*Density*V*V*0.4306*0.656168)*5);
%-0.03*0.00238*V^2*3.22917*0.5*11.6142+
%With 50 percent effectiveness
%M = ((-0.3486-3.3182*0.5*alpha+0.0975*beta0.4184*beta^2+0.3053*0.5*alpha*V)*0.5*Density*V*V*0.4306*0.656168)*5;
N = ((-0.5094*beta)*0.5*Density*V*V*0.4306*0.656168)*5 + 2*F(2);
moments = [L;M;N];
sys = [F(1) F(2) F(3) moments(1) moments(2) moments(3)] ;
end 
%mdlOutputs
%
%=============================================================================
% mdlGetTimeOfNextVarHit
% Return the time of the next hit for this block. Note that the result is
% absolute time. Note that this function is only used when you specify a
% variable discrete-time sample time [-2 0] in the sample time array in
% mdlInitializeSizes.
%=============================================================================
%
function sys=mdlGetTimeOfNextVarHit(t,x,u)
sampleTime = 1; % Example, set the next hit to be one second later.
sys = t + sampleTime;
end 
%mdlGetTimeOfNextVarHit
%
%=============================================================================
% mdlTerminate
% Perform any end of simulation tasks.
%=============================================================================
%
function sys=mdlTerminate(t,x,u)
sys = [];
end 
%mdlTerminate